/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTLIMIT or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.common.model.mission;

import javax.xml.stream.XMLStreamException;

import net.sf.freecol.common.io.FreeColXMLReader;
import net.sf.freecol.common.io.FreeColXMLWriter;
import net.sf.freecol.common.model.FreeColGameObject;
import net.sf.freecol.common.model.Game;
import net.sf.freecol.common.model.Unit;

import org.w3c.dom.Element;


/**
 * The AbstractMission provides basic methods for building Missions.
 */
public abstract class AbstractMission extends FreeColGameObject implements Mission
{

    /**
     * The Unit this mission was assigned to. Must not be null.
     */
    private Unit unit;

    /**
     * The number of times this mission should be repeated. Defaults
     * to 1.
     */
    private int repeatCount = 1;

    /**
     * The number of turns this mission will take to carry out. In
     * most cases, this will be zero, since most missions do not take
     * a fixed number of turns to carry out. Building TileImprovements
     * and learning in school would be exceptions, however.
     */
    private int turnCount;


    /**
     * Returns the Unit this mission was assigned to.
     *
     * @return an <code>Unit</code> value
     */
    @Override
    public final Unit getUnit( )
    {
        return unit;
    }

    /**
     * Creates a new <code>AbstractMission</code> instance.
     *
     * @param game a <code>Game</code> value
     */
    public AbstractMission( Game game )
    {
        super( game );
    }

    /**
     * Creates a new <code>AbstractMission</code> instance.
     *
     * @param game a <code>Game</code> value
     * @param xr a <code>FreeColXMLReader</code> value
     * @exception XMLStreamException if an error occurs
     */
    public AbstractMission( Game game,
                            FreeColXMLReader xr ) throws XMLStreamException
    {
        super( game, null );
    }

    /**
     * Creates a new <code>AbstractMission</code> instance.
     *
     * @param game a <code>Game</code> value
     * @param e an <code>Element</code> value
     */
    public AbstractMission( Game game, Element e )
    {
        super( game, null );

        readFromXMLElement( e );
    }

    /**
     * Creates a new <code>AbstractMission</code> instance.
     *
     * @param game a <code>Game</code> value
     * @param id The object identifier.
     */
    public AbstractMission( Game game, String id )
    {
        super( game, id );
    }

    /**
     * Set the <code>Unit</code> value.
     *
     * @param newUnit The new Unit value.
     */
    public final void setUnit( final Unit newUnit )
    {
        this.unit = newUnit;
    }

    /**
     * Get the <code>RepeatCount</code> value.
     *
     * @return an <code>int</code> value
     */
    public final int getRepeatCount( )
    {
        return repeatCount;
    }

    /**
     * Set the <code>RepeatCount</code> value.
     *
     * @param newRepeatCount The new RepeatCount value.
     */
    public final void setRepeatCount( final int newRepeatCount )
    {
        this.repeatCount = newRepeatCount;
    }

    /**
     * Get the <code>TurnCount</code> value.
     *
     * @return an <code>int</code> value
     */
    public final int getTurnCount( )
    {
        return turnCount;
    }

    /**
     * Set the <code>TurnCount</code> value.
     *
     * @param newTurnCount The new TurnCount value.
     */
    public final void setTurnCount( final int newTurnCount )
    {
        this.turnCount = newTurnCount;
    }

    /**
     * Returns true if the Unit this mission was assigned to is
     * neither null nor has been disposed, and the repeat count of the
     * mission is greater than zero.
     *
     * @return a <code>boolean</code> value
     */
    @Override
    public boolean isValid( )
    {
        return unit != null
                && ! unit.isDisposed( )
                && repeatCount > 0;
    }

    /**
     * Returns true if this is a valid Mission for the given
     * Unit. This method always returns false and needs to be
     * overridden.
     *
     * @param unit an <code>Unit</code> value
     * @return false
     */
    public static boolean isValidFor( @SuppressWarnings( "unusued" ) Unit unit )
    {
        return false;
    }


    // Serialization

    private static final String REPEAT_COUNT_TAG = "repeatCount";
    private static final String TURN_COUNT_TAG = "turnCount";
    private static final String UNIT_TAG = "unit";


    /**
     * {@inheritDoc}
     */
    @Override
    protected void writeAttributes( FreeColXMLWriter xw ) throws XMLStreamException
    {
        super.writeAttributes( xw );

        xw.writeAttribute( UNIT_TAG, unit );

        xw.writeAttribute( TURN_COUNT_TAG, turnCount );

        xw.writeAttribute( REPEAT_COUNT_TAG, repeatCount );
    }


    /**
     * {@inheritDoc}
     */
    @Override
    protected void readAttributes( FreeColXMLReader xr ) throws XMLStreamException
    {
        super.readAttributes( xr );

        unit = xr.makeFreeColGameObject( getGame( ), UNIT_TAG, Unit.class, true );

        turnCount = xr.getAttribute( TURN_COUNT_TAG, 0 );

        repeatCount = xr.getAttribute( REPEAT_COUNT_TAG, 1 );
    }
}
